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Document last updated: 2024-07-10


1 Metadata structure


1.1 Sampling Variables

Categorical

  • Site
    • n = 22
      • FCP - Four Canyon Preserve; Oklahoma, 36.0235,-99.9439
  • Grassland type
    • n = 4
    • tallgrass, mixed grass, shortgrass, desert
  • Grass host species
    • n = 5
      • ANGE (Andropogon gerardii / Big bluestem)
      • SCSC (Schizachyrium scoparium / Little bluestem)
      • BOER (Bouteloua eriopoda / Black grama)
      • BOGR (B. gracilis / Blue grama)
      • BUDA (B. dactyloides / Buffalograss)
  • Latitudinal Bin
    • n = 4
    • North, North Central, South Central, South
  • Longitudinal Gradient:
    • n = 3
    • East, Middle, West

Continuous

  • Elevation (in meters)
    • ranges from -20 to 2,747 m
  • Latitude
    • 29.23005 to 41.12200° N
  • Longitude
    • -108.28760 to -94.13184° W

1.2 Climate Data

Continuous

  • ppt = mean annual precipitation (determined over 3- and 30-year windows and 2015)
  • GDD = growing degree days (determined over 3- and 30-year windows and 2015)

1.3 Edaphic Variables

Continuous: (min, max values)

  • pH: (5.05, 8.36)
  • SOM (via LoI): (0.45, 11.14)
  • soil moisture: (0.65, 0.99%)
  • phosphorous: (0.171, 0.269)
  • ammonium: (0.87, 1.38)
  • nitrate: (0.35, 0.55)

1.4 Plant Traits

Continuous: (min, max values)

  • avg_SLA: specific leaf area (98.4, 191)

  • avg_SRL: specific root length (659.4, 3306.4)

    • Large values of specific leaf area (SLA) and specific root length (SRL) reflect large plant investment in resource acquisition; small values indicate investment in plant tissue longevity

  • herbivory_perc: (0, 17%)

    • average site level damage estimate for herbivory, averaged over all species and individuals at the site; could be used to indicate herbivory pressure at the site level


2 Data Standardization/Transformations


All continuous data predictors (climate, edaphic, and plant trait) were mean standardized, i.e., scaled to mean = 0 and SD = 1.

2.1 Collinearity

I assessed multicollinearity and removed correlated predictors, retaining ammonium over nitrate and soil moisture over similar measurements. For climate, only retaining 3yr values.

Viewing tables of variable-variable correlations by category. Tables have been filtered to pearson correlation values > 0.9 or <-0.9.

Sampling


Variable Category Var1 Var2 Correlation Var1 Cat Var2 Cat
Sampling Longitude Elevation_m -0.9076341 Sampling Sampling

Climate


Variable Category Var1 Var2 Correlation Var1 Cat Var2 Cat
Climate GDD3yr_m.std GDD2015_m.std 0.9962364 Climate Climate
Climate ppt3yr_m.std ppt2015_m.std 0.9513075 Climate Climate
Climate ppt30yr_m.std ppt3yr_m.std 0.9415934 Climate Climate
Climate ppt30yr_m.std ppt2015_m.std 0.9071337 Climate Climate

Retaining GDD3yr over GDD2015 (degree growing days) & similarly, ppt3yr (mean annual precipitation)

Edaphic


Variable Category Var1 Var2 Correlation Var1 Cat Var2 Cat
Edaphic ammonium_m.std nitrate_m.std 1.0000000 Edaphic Edaphic
Edaphic phos_m.std ammonium_m.std 0.9868129 Edaphic Edaphic
Edaphic phos_m.std nitrate_m.std 0.9868129 Edaphic Edaphic

Retaining soil_moisture over GWC and percent soil moisture (complement). Retaining ammonium over nitrate because Rudgers2021 did. I am considering removing phos.

Plant Trait


n/a


Mixed


Variable Category Var1 Var2 Correlation Var1 Cat Var2 Cat
Mixed Longitude ppt30yr_m.std 0.9525351 Sampling Climate
Mixed Longitude ppt3yr_m.std 0.9050114 Sampling Climate


Precipitation is highly correlated to longitude. Interesting…

3 Summary stats of variables

For these variable summaries, I am showing non-standardized/raw data values.

Latitude

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 29.23 31.96 34.98 35.15 39.07 41.12

Histograms of Latitude

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

Longitude

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. -108.29 -104.53 -98.91 -100.25 -97.52 -94.13

Histograms of Longitude

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

Elevation_m

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. -19.8 335.0 635.0 917.3 1551.0 2747.0

Histograms of Elevation_m

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

pH

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 5.050 6.670 7.250 7.124 7.770 8.360

Histograms of pH

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

SOM

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 0.4508 2.0087 4.3897 4.4057 6.8384 11.1393

Histograms of SOM

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

soil_moisture

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 0.6474 0.8291 0.8780 0.8705 0.9333 0.9889

Histograms of soil_moisture

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

phos

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 0.1705 0.1841 0.1937 0.1975 0.2028 0.2690

Histograms of phos

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

ammonium

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 0.8722 0.9233 0.9976 1.0096 1.0470 1.3796

Histograms of ammonium

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

ppt3yr

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 188.4 415.2 606.2 616.5 858.3 1064.2

Histograms of ppt3yr

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

GDD3yr

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 2048 3930 4427 4475 5010 6005

Histograms of GDD3yr

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

avg_SLA

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 98.42 124.81 140.01 141.69 155.90 191.04

Histograms of avg_SLA

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

avg_SRL

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 659.4 1523.6 1723.4 1857.6 2150.4 3306.4

Histograms of avg_SRL

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

herbivory_perc

Summary Statistics:

Min. 1st Qu. Median Mean 3rd Qu. Max. 0.000 1.042 2.625 3.450 4.479 17.000

Histograms of herbivory_perc

All Sites

By Site

By Grass

By Fun Clusters

By Bac Clusters

4 Check variance of variables

[tbd]